Rivets: A Versatile and Long-Lasting Fastening Solution(cnc turning machine Neil)
- source:EAGLEBURGER CNC Machining
With ongoing advancements in rivet technology and designs, rivets deliver superior strength, durability, and versatility across a wide range of applications. Let's take a closer look at what makes rivets such an indispensable fastener and some of their most common uses today.
What are Rivets?
A rivet is a two-part mechanical fastener that consists of a smooth cylindrical shaft and a head. The rivet is inserted into pre-drilled holes through the materials being joined. The excess portion of the shaft extends out the other side and is mechanically deformed with a tool to form the second head. This process is called riveting or setting the rivet.
The setting action spreads the rivet shaft, forming a second head and clamping the materials together. The resulting riveted joint is permanent and holds the materials together dependably even when subjected to shock, vibration, and other forces.
Benefits of Rivets
There are many good reasons why rivets have endured as a preferred connecting method across so many industries and applications. Here are some of the primary benefits that make rivets a top choice:
- High strength and durability: When properly set, rivets form a tight connection that resists shearing and axial forces extremely well. Rivet joints typically last the lifetime of the materials they are set in.
- Vibration and shock resistance: The upsetting during rivet setting work-hardens the shaft, while also mechanically clamping materials. This makes rivet joints resistant to loosening under vibration, shock loads, and fatigue.
- Low profile: Rivet heads have a relatively low profile compared to many other fasteners. This is advantageous when a joint needs to be as streamlined as possible.
- Quick installation: Riveting is generally faster than welding, screwing, or gluing. It takes just a few seconds to set most rivets using modern pneumatic tools.
- Easy inspection: Installed rivets are easy to visually inspect to check for proper setting. Loose rivets are also obvious upon inspection.
- Cost effective: Rivets themselves are inexpensive. And riveting tools and equipment have low acquisition and maintenance costs compared to other fastening methods.
- Weight savings: Rivets allow thinner and lighter material gauges to be joined than other techniques like welding. This reduces weight, which is especially beneficial in structures and vehicles.
- Materials versatility: Rivets can join dissimilar metals, composites, plastics, glass, stone, wood, and many other materials. Specialty rivets are available for unique material combinations.
- Corrosion resistance: Many rivet alloys, coatings, and finishes provide excellent corrosion resistance and weatherability. This allows their use in harsh environments.
Common Applications of Rivets
Thanks to their list of benefits, rivets serve as a trusted fastening solution in a diverse range of applications. Some of the most prevalent uses include:
Aircraft and Aerospace
Rivets are extensively used in both civilian and military aircraft and spacecraft. Aluminum and titanium are frequently riveted in airframes and engine nacelles. Rivets meet the high demands for strength per weight in airborne applications. Specialty flush head rivets improve aerodynamics. And extensive inspection and maintenance procedures ensure reliable performance.
Automobiles and Trucks
From chassis to body panels, rivets are ubiquitous in vehicle manufacturing and repair. Riveting aluminum helps minimize weight. Self-piercing rivets allow steel and high-strength steel alloys to be joined with no hole drilling. Large structural rivets connect truck frames. And specialty micro rivets assemble electronics components and subassemblies.
Appliances and Consumer Goods
Behind the scenes of many household products like washing machines, HVAC equipment, and small kitchen appliances are rivets joining essential parts and casings. The speed of automated riveting makes it ideal for high-volume production. And rivets outperform threaded fasteners in resisting loosening from vibration.
Construction and Infrastructure
In steel structure buildings, bridges, towers, and equipment like cranes, large structural rivets are a standard fastening method. Riveting's ability to join sections reliably even decades later makes it advantageous for critical structural applications. Stainless steel rivets withstand weather exposure in civil structures.
Marine and Offshore
The marine industry relies heavily on rivets due to their corrosion resistance in ocean environments. Ship hulls, decks, bulkheads and more all employ rivets. Offshore oil platforms use rivets throughout their structures and equipment. Custom large head rivets minimize water intrusion risk.
Rail and Mass Transit
Passenger railcars and subway cars have extensive riveted assemblies. Riveting aluminum helps minimize weight for fuel efficiency. Rivets perform reliably despite constant rattling and vibrations. Critical components like coupler assemblies and bogies are riveted for maximum strength and safety.
From jogging strollers to patio furniture, rivets assemble all types of recreational gear reliably and cost-effectively. Their vibration resistance keeps components tightly fastened even with repeated use. Flush rivets provide clean aesthetics important in consumer products. Weight savings help maximize performance in bicycles and other sporting goods.
The popularity and longevity of rivets across such diverse applications speaks to their capabilities as a versatile, high-performing, and cost-competitive fastening solution. While manufacturing techniques continue advancing, the basic rivet design remains valid after centuries of proven performance. With ongoing innovations in rivet materials, coatings, setting methods, and automation, rivets will surely continue fulfilling critical fastening needs for the foreseeable future.
Types of Rivets
With myriad uses across virtually every industry, many types of rivets have been developed to meet different joint requirements. Here is an overview of some of the most common varieties:
The most traditional type, solid shank rivets are one piece and made entirely of the base rivet alloy. Common alloys include steel, aluminum, copper, and Monel. They are economical and have good shear strength, especially in soft materials.
These contain an internal collar that is drawn into the rivet as it is set to form the back head. Blind rivets can be installed from one side when there is only access to a single surface. They are popular for panels, ducting, and thin sheet assemblies.
These feature a split shaft that folds outward during setting. This allows use in only roughly aligned holes. The split shaft also helps compensate for differences in material thicknesses.
Here, the rivet has a small center hole allowing it to be driven much like a screw. Drive rivets can be removed and reused repeatedly if needed. They are advantageous in temporary or adjustable assemblies.
Large Structural Rivets
For joining thick and heavy components like steel I-beams, large structural rivets from 3/8” to over 1” diameter are required. Their shafts can be several inches long. Structural rivets are set with heavy hydraulically powered tools.
As their name describes, these rivets pierce and interlock thin sheets in a single process without pre-drilling. Self-piercing rivets are ideal for different materials and sheet gauges. Automotive panels are frequently joined with self-piercing rivets.
Tiny micro rivets with diameters smaller than 0.8 mm are ideal for precision electronics and small assemblies. Semi-automated tools allow high-speed installation. Micro rivets continue getting even smaller as electronics components shrink.
The variety of rivet types and huge range of sizes means the ideal rivet solution can be selected for virtually any application requirements. Manufacturers offer extensive catalogs covering just about every joining need imaginable. Beyond the basics described here, rivets also come with specialty coatings, colors, drive types, mixed materials, countersunk heads, and more.
Rivet Materials and Finishes
With rivets utilized across so many products and industries, many material options are available to provide desired qualities like strength, corrosion resistance, appearance, and cost. Here are some of the most common rivet materials and finishes:
A lightweight, strong material ideal for aircraft, automobiles, appliances, furniture, and other products. Various aluminum alloys help tailor strength, ductility, and corrosion resistance. Anodizing improves wear and abrasion resistance.
The wide range of steel alloys allows cost-effective rivets with the required levels of strength, hardness, and environmental resistance. Carbon steels, stainless steels, and alloy steels are all readily riveted.
Copper and Brass
These naturally corrosion resistant metals make excellent rivet choices for long-lasting outdoor products and hardware. Brass coated steels gain similar environmental durability.
Though more costly, titanium rivets offer the highest strength-to-weight ratio and withstand extreme environments. Aerospace applications utilize titanium rivets extensively.
Various plastic polymers mold into specialty rivet designs ideal for products like toys, furniture, electronics, signs, and recreational gear.
Beyond basic metals and polymers, unique rivet materials for extreme demands include beryllium copper, Inconel nickel alloy, magnesium, tungsten, and molybdenum. Practically any drillable and deformable metal can be made into a rivet.
Rivet coatings and platings are also important for enhancing corrosion and abrasion resistance and attaining desired aesthetics:
- Zinc, tin, and cadmium coatings help prevent rust and tarnish on steel.
- Nickel, chrome, and silver finishes improve appearance and conductivity.
- Painted and powder coated rivets come in many colors to match or accentuate materials.
- Plastics can be used to coat specialty rivet types like drive rivets and blind rivets.
So whether the goals are light weight for aircraft, weather resistance for a skyscraper, or matching colors for a motorcycle, rivets can be fabricated with exactly the needed properties.
How Rivets Are Manufactured
While ancient rivets were hand forged, today’s high volumes demand automated and precision manufacturing. Here is an overview of modern industrial rivet production:
The rivet manufacturing process starts with rods, wires, bars, extrusions, sheets, or other forms of the base rivet material like steel, titanium, brass, or polymers. Materials are selected to meet strength, hardness, corrosion, weight, cost, and other requirements.
Metals destined to become rivets are heated to increase malleability for deformation into rivet wire. Induction heating rapidly brings bars or rods to ideal working temperatures above 1600°F for steel and aluminium and over 2200°F for titanium.
Hot upset forging machines then transform the heated round bars into the shape of rivet wire - a wire form with a head on one end. Sophisticated closed die forging shapes rivet heads and shafts precisely with smooth finishes.
The continuous lengths of hot forged rivet wire are trimmed to form individual rivets to the exact required lengths, typically using high speed flywheel cutters. Precise length influences rivet strength and setting behavior.
Further steps enhance rivet mechanical qualities and appearance. Annealing relieves stresses from forging. Shot peening work hardens surfaces to resist fatigue and wear. Coatings are electroplated or painted on. And some heads are machined to add grooves, recesses or drive bits.
Automated vision systems, sieves, magnets, and other methods sort finished rivets by size, geometry, and attributes. Precise sorting ensures fasteners match applicable specifications before packaging.
Counters, weighers, and baggers package sorted rivets into cartons, tubes, boxes, or bags based on quantities needed for particular manufacturing or field assembly purposes. Bulk cases contain thousands of rivets.
The fast and flexible automated process produces billions of rivets annually to meet the needs of industrial and commercial manufacturers across many fields. In fact, over 75 billion rivets are estimated to be produced globally each year.
Today’s advanced technology and automation allow rivet producers to cost-effectively supply industry with an extensive range of precisely crafted rivets in everything from tiny micro sizes for electronics up to massive structural rivets that require heavy hydraulic riveters to install. Thanks to modern manufacturing techniques, rivets are now cleaner, stronger, more uniform, and cheaper than ever before.
While rivet manufacturing has progressed considerably, installation methods remain relatively unchanged - a rivet is still set by mechanically upsetting the free shaft end to expand it. However, tools and techniques continue evolving to improve quality, speed, automation, and ergonomics. Here is an overview of common riveting methods:
The traditional approach uses hand tools like hammers, mallets, and bucking bars. It requires access to both rivet head sides and reasonable operator skill. Hand riveting is still used for repairs, small production runs, and field assembly.
These rivet guns use compressed air power, making setting fast and easy. Pneumatic squeezers upset the rivet directly. Hammer types strike a rod to form the second head. Production shops use pneumatic tools extensively for productivity and quality.
Cordless battery powered tools provide pneumatic rivet gun performance anywhere without air hookups. Electric power and brushless motors enable high speed, precision riveting for field work and small production runs.
Powerful hydraulic squeezers and hammers drive large structural rivets up to 1-1/4” diameter. They develop over 50 tons of force for dependable, full upsetting even on thick, heat-treated steels. Structural fabrication uses these heavy riveters.
Robotic riveting systems boost output and quality in high-volume manufacturing. Multi-axis articulated arms outfitted with specialized rivet heads can install thousands of fasteners per shift with speed, accuracy, and repeatability surpassing manual methods.
Riveting tools range from simple hand squeezers and hammers used for decades to advanced robotic systems designed for today’s automated factories and precise quality standards. While installations basics remain unchanged, modern tools make the riveting process faster and more efficient than ever.
Inspection and Testing
To ensure optimal performance of riveted assemblies, proper inspection and testing is critical during manufacturing:
Rivet setting force and button diameter are monitored to confirm adequate deformation without excessive material deformation. Operators perform visual inspection of upset rivet tails. Statistical sampling checks dimensional conformance.
Test coupons confirm minimum rivet spacing, edge distance, and other joint design specifications are fulfilled. Shear and tensile testing verifies riveted joint strength meets requirements.
Periodic measurement of set rivet parameters validates that tools and operators remain in proper calibration over time. Testing establishes process capability and acceptable variance.
X-ray, ultrasonic, and other NDT methods pinpoint any hidden flaws or defects in production rivet joining. Especially important for aircraft, aerospace, and critical applications.
Extensive quality control data provides traceability and proof of compliant riveting work. Statistical tracking helps identify any potential issues requiring process adjustments.
Thorough rivet inspection and testing ensures reliability, reveals any assembly issues, and provides accountability expected in today's quality-focused manufacturing world.
The Future of Rivet Technology
While rivets have been used since ancient times, they are far from outdated and obsolete. Continued technological advancements in materials, coatings, designs, automation, and installation processes will enable rivets to perform even better and continue meeting fastening challenges as they arise.
Some emerging riveting technologies that hint at the ongoing evolution of this vital fastening solution include:
- New superalloys like titanium-tantalum expand use in extreme environments. Coatings like diamond-like carbon increase hardness and wear resistance.
- Grooved and notched heads are becoming more common to enhance grip and joint strength. Mechanical interlock designs improve resistance to rotation and vibration.
- Blind rivets using exotic shape memory alloys provide temperature-activated clamping pressure. This compensates for joint slippage from thermal expansion and contraction.
- Structural adhesive dispensing rivet heads allow joints to be bonded and riveted simultaneously for exceptional durability.
- Online quality monitoring systems inspect set rivets in real-time using AI-enabled computer vision technology.
- Automated riveting robots with advanced sensing and process controls will help improve quality, precision, consistency, and analysis.
- New portable, battery-powered rivet tools increase ease of use and flexibility for field work and maintenance.
The continued emergence of innovative materials, rivet types, automated systems, quality assurance methods, and more will enable rivets to continue excelling as a preferred fastening choice across industrial, commercial, and consumer sectors. After playing a central role in fabrication for millennia, this simple yet profoundly useful fastener still has an enduring and pivotal future ahead. CNC Milling CNC Machining